The invention relates to a device for conducting biochemical and microbiological reactions according to the preamble of claim 1.
It has been known in the art to use a microtiter plate with 96 vessels for concurrently carrying out a plurality of molecular biological reactions, such as e.g., the polymerase chain reaction (PCR). After the vessels of the microtiter plate are filled with the reaction solution, they are covered with a foil. While the PCR is being carried out, the foil is pressed against the microtiter plate by means of a heatable cover. The known method is quite time-consuming since relatively large quantities of reaction solution have to simultaneously undergo a temperature treatment that has to be accurately performed.
U.S. Pat. No. 5,455,175 shows a so-called thermocycler that permits to repeatedly expose a plurality of liquid biological samples to a predetermined temperature profile for carrying out PCR. In order to shorten the time required for temperature treatment, a small volume of biological samples at a time is accepted in a thin-walled glass capillary tube. For this purpose, each sample must be filled individually into the capillary tube and then welded. Sample preparation is time-consuming.
The generic DE-OS 44 12 281 A1 describes a system for carrying out reaction processes in a contamination-free fashion. The system includes reaction vessels, individual lids for the reaction vessels and a device for automatically opening the individual lids. In a closed position, the lid projects into the space surrounded by the reaction vessel. This enables the device to engage and, as a result thereof, the individual lids to open automatically.
U.S. Pat. No. 4,599,314 discloses a support into which a plurality of reaction vessels may be inserted. The covers intended to close the reaction vessels may be jointly lifted off the reaction vessels by means of a plate provided with an adhesive tape. The time required for carrying out the reactions is not substantially reduced thereby.
It is the object of the present invention to overcome the prior art disadvantages. More specifically, it aims at more specifically indicating a device that makes it possible to concurrently carry out a plurality of biochemical or microbiological reactions with little time expenditure.
This object is achieved by the features of claim 1. Appropriate embodiments will arise out of the features of the claims 2 to 21.
According to the invention, there is provided that an inner side of the closing means that faces the reaction vessel is coated with a molecule on which a molecule to be detected can be bonded or deposited, wherein the molecule contains a nucleic acid, an amino acid or a synthetic derivative of a nucleic or amino acid.
The molecule may be a nucleic acid probe, a gene, a peptide, protein, PNA (=peptide nucleic acid), PTO (phosphorothioate) or the like. When using a nucleic acid probe, the bonding and depositing capacity of the molecule to be detected consists in hybridization with a nucleic acid that is complementary to the nucleic acid probe. In case a peptide or a protein is used as a molecule, an antigen/antibody bond may form with the molecule to be detected. The molecule has the property to specifically bond to the molecule to be detected.
The device according to the invention permits to carry out microbiological reactions in a particularly quick and efficient way. Since the closing means projects into the space surrounded by the reaction vessel, only small volumes of sample are required. A therein potentially contained molecule to be detected may be quickly and efficiently amplified by means of PCR for example.
The closing means of preference is a cover made of synthetic material and is preferably transparent. Such a cover is inexpensive. It may be designed as a one-way product.
The pressing device may be provided with a projection that conforms to the shape of the cavity. The cavity is thus readily sealed.
The closing means may also be a foil that is made of a synthetic material, is flexible and preferably transparent. The foil serves to further seal a cavity closed by a projection.
According to another feature of the embodiment, the pressing device is provided with a location facility for the cover(s). As a result thereof, the cover(s) may be placed automatically.
The location facility may be appropriately designed as a tube or a rod for frictional engagement of a separate cover. A facility for removably fastening the cover may also be provided in the vicinity of the free end of the tube or rod. It may be an U-shaped profile that projects radially outward, one of its legs being connected to the tube and the other leg being shorter than the one leg. Such a facility readily allows the location of a cover. For this purpose, the cover is appropriately provided with an outward projecting rim that corresponds to the U-shaped profile. The rim and the matching U-shaped profile advantageously extend over two peripheral sections of about 90xc2x0. The location element may be rotatable about approximately 90xc2x0. By using the embodiment of the rim and of the matching U-shaped profile as they have been described herein above, a simple location of the cover may be achieved by way of such a rotation.
Each location element may additionally be axially movable. This allows to press on and take off certain covers separately.
According to a further embodiment, a throwing off element may be provided, said throwing off element coaxially surrounding the location element and being movable relative to said location element. This allows covers that are, e.g., held on the location element by frictional engagement to be thrown off.
The covers may of course not only be held on the location facility by frictional engagement, they may also be fastened to it by means of a releasable snap connection. For this purpose, a location facility designed as a rod or a tube may be provided on its outer periphery with a radially contouring bulge that cooperates with a corresponding groove on the inner wall of the cover.
Advantageously, there is provided between a plurality of location elements at least one punch that is movable relative to the location elements. This facilitates the simultaneous release of several covers.
It is deemed particularly advantageous to have the projection, the tube or the rod provided with optical waveguides for introducing light into or for observing light produced in the cavity, respectively. The optical waveguides may be connected to a source of light and/or to a facility for detecting fluorescence. This allows to conduct the procedure in a particularly rapid and efficient manner.
Advantageously, a plurality of reaction vessels are provided and the reaction vessels are part of a microtiter plate. Reaction vessels designed in such a way may be employed, e.g. in conventional thermocyclers for carrying out PCR. When the reaction vessels are thus formed, a plurality of covers may be part of a cover plate. This facilitates closing and opening.
It is deemed particularly advantageous to have the cover, at least in the zone of the coating, made of an electrically conductive synthetic material, preferably of an electrically conductive polycarbonate. Such an electrically conductive polycarbonate may be made by adding graphite or graphite fibers, respectively. Intrinsically conductive synthetic materials such as polyaneline, or polyacetylene may also be utilized, though. The electrically conductive zone may be contacted. As a result thereof it is possible to, e.g., apply a potential over the sample solution and to cause the charged molecules to be detected that are contained in the sample to move in the direction of the coating. It is however also possible to prove bonding or deposition of the molecules to be detected to the molecule of the coating by means of voltammetric methods.